Advertisement

Advertisement

Extreme cure for MS reboots immune system – but can be fatal

A radical treatment for multiple sclerosis has stopped the disease progressing in 70 per cent of those who have tried it, but one person in the trial died

MRI scans of a healthy brain (left) and one with multiple sclerosis (right)

Jessica Wilson/Science Photo Library

By Clare Wilson

It’s a terrible dilemma: a treatment that might cure you or kill you.

This is what some people with severe multiple sclerosis now face. A radical approach that wipes out the immune system and then reboots it with stem cells has stopped the devastating disease in its tracks in 70 per cent of the people who have tried it. But of the 24 people taking part in the trial, one died from liver damage and an infection while their immune system was impaired.

Advertisement

“I took a leap of faith. I felt like I would be kicking myself if I didn’t take this chance,” says Jennifer Molson of Ontario Canada, who had the treatment. When she decided to try it 14 years ago, she was using a wheelchair. About 18 months later, she began to notice physical improvements, and within three years she had gone back to work. Today, her life has returned to normal.

In multiple sclerosis, the immune system attacks the protective coating around nerve cells in the brain, spinal cord and optic nerves. It tends to come and go in flare-ups that get worse over time, and can eventually leave people paralysed and blind. Existing drug treatments can lessen the severity or frequency of attacks but are not a cure and don’t work for some.

Although the immune reboot is only supposed to stop MS, not reverse it, some people regained much of their functioning in the years that followed, suggesting the nervous system slowly repairs itself if the damage is not too severe.

Accidental cure

The treatment was discovered in people with leukaemia who also happened to have MS. Leukaemia is a cancer of the immune cells, and can be treated by first extracting some of a person’s bone marrow cells and then killing all the immune cells that remain in the body with toxic chemotherapy.

The stored bone marrow sample is then purged of cancerous cells and injected into the person’s blood to repopulate their immune system. Surprisingly, this treatment happened to be effective not only for leukaemia but also MS.

We don’t know what makes immune cells attack nerve cells in MS. One theory is that it is triggered by viruses that have similar proteins to those on the surface of human nerve cells. It could be that rebooting the immune system cures MS because any memory of a virus like this is wiped out.

Several centres around the world are now offering this procedure as an experimental treatment for people who have an aggressive form of MS and who are not benefiting from standard drugs. Because of the serious risk of infection while the immune system is down, most places offer a milder form of chemotherapy, but this makes it more likely that some of the nerve-targeting immune cells will survive.

Radical treatment

The regime in the latest study – which began in 2000 but was published this week – is more intense, designed to kill all the immune cells in a person’s body. “It’s important that patients recognise that this is not a cakewalk,” says Mark Freedman of Ottawa Hospital Research Institute in Ontario.

As well as the risk of infection, people lose their hair and fingernails, and suffer nausea and diarrhoea. The chemotherapy renders them infertile by killing sperm or eggs, and pushes women into early menopause. They tend to stay in hospital for a month, with their new bone marrow infused around day 11, before the last of their old immune cells have died off.

But infection is still a grave risk. Freedman hopes that as the approach is refined, the death rate will come down. At the moment it is about 1 per cent of those treated, he says, not as bad as the 4 per cent that the 24-person trial suggests. The team is now using a different version of one of the chemotherapy drugs that is less likely to cause the liver complications that may have contributed to the person’s death in this study.

John Snowden of Sheffield Teaching Hospital in the UK says that less intense chemo regimes – such as the one his centre uses – are a safer option. “We still need to find the sweet spot between toxicity and effectiveness,” he says.

The approach of rebooting the immune system is also being investigated for other severe autoimmune diseases. These include Crohn’s disease, in which the immune system attacks the bowel, and a rare skin condition called scleroderma.